Migratory movements of waterfowl in Central Asia and avian influenza emergence: sporadic transmission of H5N1 from east to west

Waterfowl in the genera Anas and Tadorna are suspected as vectors in the long‐distance transmission of highly pathogenic avian influenza H5N1. The former Soviet Republics of Central Asia are situated at an important migratory crossroads for these and other species of birds that bridges regions where the disease is prevalent. However, waterfowl movements through Central Asia are poorly quantified. In this study, historical data derived from over 80 years of bird ringing are combined with recent satellite tracking data to delineate migration routes, movement chronology and habitat use patterns of waterfowl in relation to H5N1 outbreak locations. Results confirm migratory linkage between breeding and moulting areas in northern Kazakhstan and southern Siberia, with non‐breeding areas in the Caspian, Black and eastern Mediterranean Sea basins, as well as with South Asia. However, unlike the situation in neighbouring regions, most notably western China, H5N1 outbreaks have not been recurrent in Central Asia after they were first reported during summer 2005 and spring 2006. These findings have implications in relation to potential sampling biases, species‐specific variation in migratory behaviour and continuing regional H5N1 transmission risks.     

Effects of sample size,number of markers,and allelic richness on the detection of spatial genetic pattern

The influence of study design on the ability to detect the effects of landscape pattern on gene flow is one of the most pressing methodological gaps in landscape genetic research. To investigate the effect of study design on landscape genetics inference, we used a spatially‐explicit, individual‐based program to simulate gene flow in a spatially continuous population inhabiting a landscape with gradual spatial changes in resistance to movement. We simulated a wide range of combinations of number of loci, number of alleles per locus and number of individuals sampled from the population. We assessed how these three aspects of study design influenced the statistical power to successfully identify the generating process among competing hypotheses of isolation‐by‐distance, isolation‐by‐barrier, and isolation‐by‐landscape resistance using a causal modelling approach with partial Mantel tests. We modelled the statistical power to identify the generating process as a response surface for equilibrium and non‐equilibrium conditions after introduction of isolation‐by‐landscape resistance. All three variables (loci, alleles and sampled individuals) affect the power of causal modelling, but to different degrees. Stronger partial Mantel r correlations between landscape distances and genetic distances were found when more loci were used and when loci were more variable, which makes comparisons of effect size between studies difficult. Number of individuals did not affect the accuracy through mean equilibrium partial Mantel r, but larger samples decreased the uncertainty (increasing the precision) of equilibrium partial Mantel r estimates. We conclude that amplifying more (and more variable) loci is likely to increase the power of landscape genetic inferences more than increasing number of individuals.     

阿片肽对大鼠伏核神经元突触后电位的影响

行为学研究指出,伏核是阿片奖赏作用,和阿片成瘾的关键脑区域,为了在细胞水平上分析阿片作用机理,本文在大鼠伏核脑片制备上,应用细胞内电流箝记录,于不同神经元上分别观察三种阿片肽对膜电位和突触后电位的影响,研究结果表明：所试验的三种阿片肽均不影响神经元的膜电位和输入阻抗,却降低突触后电位;纳洛酮明显地翻转μ和δ受体激动剂的作用,对Ｋａｐｐａ受体激动剂作用翻转不完全。上述结果提示：在伏核内,阿片肽的作用     

Effect of Lithium on Concentrations of Glutamate and GABA Levels in Amygdala and Hypothalamus of Rat

LITHIUM salts have been used to treat manic-depressive psychosis^1,2 and reduce aggressive behaviour in animals^3–5. The hypothalamus and limbic structures, known to be involved in emotional behaviour, responded to lithium with specific changes in electrolyte distribution⁶ and EEG pattern⁷, respectively. “Attack” and “flight” behaviour associated with hypothalamic sites was evoked by glutamate and blocked by γ-aminobutyric acid (GABA)⁸. We have, therefore, studied the effects of lithium treatment, acute and prolonged, on the glutamate and GABA levels in the amygdala and hypothalamus of the rat.     

ONTOGENY AND RELATIONSHIPS OF THE TRILOBITE PSEUDOPETIGURUS PRANTL AND PŘIBYL

Abstract:  The ontogeny of Pseudopetigurus deprati Turvey et al ., 2006 from the Ordovician Dawan Formation (Arenigian), Anhui Province, South China, is described. The presence of an anterior cranidial border in Pseudopetigurus is recognized for the first time. On account of the short (tr.), spindle-shaped anterior border, and the distinct, steeply inclined, wall-like pygidial margin, Pseudopetigurus is assigned to the family Dimeropygidae, the first genus of this family endemic to Gondwana. It has previously been regarded as a member of family Isocolidae. Cladistic analysis of species assigned to Dimeropygidae supports the monophyly of a clade including Dimeropyge , Dimeropygiella , Ischyrotoma , Pseudohystricurus and Pseudopetigurus , which may represent a subfamily Dimeropyginae. The distribution of Dimeropyginae shows a predominantly palaeotropical distribution, while the Gondwana Pseudopetigurus must have diverged from the dimeropygine common ancestor in pre-Arenigian time.     

Deer Carcass Decomposition and Potential Scavenger Exposure to Chronic Wasting Disease

ABSTRACT Chronic wasting disease (CWD) is a transmissible spongiform encephalopathy afflicting the Cervidae family in North America, causing neurodegeneration and ultimately death. Although there are no reports of natural cross-species transmission of CWD to noncervids, infected deer carcasses pose a potential risk of CWD exposure for other animals. We placed 40 disease-free white-tailed deer (Odocoileus virginianus) carcasses and 10 gut piles in the CWD-affected area of Wisconsin (USA) from September to April in 2003 through 2005. We used photos from remotely operated cameras to characterize scavenger visitation and relative activity. To evaluate factors driving the rate of carcass removal (decomposition), we used Kaplan-Meier survival analysis and a generalized linear mixed model. We recorded 14 species of scavenging mammals (6 visiting species) and 14 species of scavenging birds (8 visiting species). Prominent scavengers included American crows (Corvus brachyrhynchos), raccoons (Procyon lotor), and Virginia opossums (Didelphis virginiana). We found no evidence that deer consumed conspecific remains, although they visited gut piles more often than carcasses relative to temporal availability in the environment. Domestic dogs, cats, and cows either scavenged or visited carcass sites, which could lead to human exposure to CWD. Deer carcasses persisted for 18 days to 101 days depending on the season and year, whereas gut piles lasted for 3 days. Habitat did not influence carcass decomposition, but mammalian and avian scavenger activity and higher temperatures were positively associated with faster removal. Infected deer carcasses or gut piles can serve as potential sources of CWD prions to a variety of scavengers. In areas where surveillance for CWD exposure is practical, management agencies should consider strategies for testing primary scavengers of deer carcass material.